Jean-Marie Guéhenno, the UN's under-secretary-general for peacekeeping operations, will arrive for a two-day visit to Brussels today (Thursday) where he will meet EU ambassadors and foreign policy chief Javier Solana.

Guéhenno's visit follows a request for the EU to send troops to support the 17,000-strong UN presence in Congo, known as MONUC, in time for parliamentary elections scheduled for 29 April.

The initial request was sent to Jack Straw, the UK foreign secretary, at the end of December.

No agreement has yet been reached and discussions are said by diplomats to be in the exploratory phase.

But it seems likely the EU would be asked to provide back-up assistance in case of any major disturbances during the polls, acting largely as a deterrent force.

According to diplomats, the matter is being discussed in "a constructive spirit". One option on the table is to deploy an EU battle group - a small multinational unit ready to respond rapidly to crises.

If the EU members agreed to the UN request for intervention, it would be the Union's second major military operation in the troubled African republic after a mission to stabilise the north-eastern town of Bunia ended in September 2003.

The EU currently runs two other operations in the country - training the Congolese police and assisting with the reform of the security sector.

The parliamentary poll is the last in a series of democratic votes - the first since independence over 45 years ago - marking the country's transition. A presidential election is scheduled for March.

But obstacles remain. Congo's parliamentarians are still refusing to pass the electoral law approved by the country's council of ministers because of objections to the method of listing candidates, raising doubts that the elections will go ahead as scheduled.

The killing of eight Guatemalan UN peacekeepers in Garamba National Park and the increasingly violent clashes with Mayi-Mayi militias in Katanga Province have highlighted the risks involved in an EU mission.

Diplomats monitoring the country said this week that the situation remained unpredictable with protests and gatherings escalated by agents provocateurs. But one diplomat said: "We haven't got any assessment that it [the risk of disturbance] is a major factor at this time of the process."

Foreign ministers will meet in Brussels on Monday (30 January) and are expected to discuss the mater. It is not yet clear if a response will be given at the meeting.